Alexander Skarsgård is no stranger to talented co-stars, having shared screen time with Liam Neeson, Ellen Page and even dad Stellan Skarsgård, but none was quite so adorable as 7-year-old Onata Aprile, whom the actor stars alongside in the drama "What Maisie Knew."

The film, based on the novel by Henry James, tells the story of a young girl who's caught in the middle of her parents' messy divorce and even messier life after. She eventually finds an unexpected father figure in her timid stepfather Lincoln, played convincingly by Skarsgård. In fact, the pair's chemistry and admiration for one another is so palpable, people just can't quit talking about it. Including Skarsgård, who told MTV News his young co-star was the main selling point of the project.

"Working with Onata was pretty amazing," he said. "Looking back, that's what I take from it. I had so much fun working with Onata."

Aprile wasn't in place when Skarsgård signed on for the role, so it was the strength of the narrative and directors Scott McGehee and David Siegel that originally lured him in.

"I thought it was a really great story, great script," he said. "I'd read the novel before. I thought it was a really interesting take on it, and I'd seen 'The Deep End' — David and Scott's film with Tilda Swinton. It's a really good film. I met the guys, and it felt like Lincoln was a character I hadn't played before, so it felt like something that would definitely be challenging for me, so that's how I got excited about it."

The kicker, though, was casting Aprile, whose performance could make her this year's Quvenzhané Wallis.

"We met a couple of young girls for Maisie, and some of them were really, really good, but one day, David and Scott sent me a tape from New York and said, 'We met someone who we think...we might have found the one,'" he recalled. "I saw the tape, and you can tell from just two seconds — so I flew out to New York, and we met at David's house, just hung out an afternoon and played...played around with a couple of the scenes, as well."

And the rest, as they like to say around these parts, is history. For Skarsgård, working with someone as unrehearsed and natural as Aprile was a unique opportunity.

"When you shoot a film with Julianne Moore and Steve Coogan, just phenomenal, phenomenal actors, and then you get to work with Onata, and it's someone who hasn't been in the industry for 30 years and hasn't done plays and movies and has this amazing..." he petered off, before addressing Aprile: "It feels weird talking about you cause you're sitting right here," he said with a grin, playfully covering Aprile's ears before continuing: "...who's got this amazing energy, and it's so real. There's not a single false note, and it makes my job really easy."

"What Maisie Knew" is playing now in New York. The film opens in L.A. on May 17, going wide on the 24th.